Response of Granular Soil along Constant Stress Increment Ratio Path

The stress‐strain response of a granular soil along constant stress increment ratio paths is experimentally investigated for the condition of σ2=σ3. Since the strains manifested along such paths can be very small, several measures have been developed to improve the accuracy of the strain measurements. A more accurate method of isolating the elastic strain has also been developed to enable reliable determination of plastic strain increment ratio. Test data unambiguously indicate that the elastic response is anisotropic, and the degree of anisotropy increases with the principal stress ratio. The plastic strain increment ratio so deduced from test data is dependent on the stress increment ratio, but can be predicted by combining Rowe's stress dilatancy equation and the energy equation of the Cam‐Clay model. This leads to a new method of predicting the stress‐strain response along such paths. The input parameters can be determined from constant σ3 tests and constant principal‐stress ratio tests. Excellent agreement with test results is achieved.